This invention relates to the parenteral nutrition of patients. It is particularly concerned with providing caloric nutrition via lipid emulsions.
Lipid emulsions for parenteral nutrition are available commercially or can be manufactured in accordance with known processes. Generally, such emulsions have been made using the triglycerides of long chain fatty acids (LCTs). LCTs are obtained conventionally from soybean or safflower oil. Long chain fatty acids are fatty acids having 14 or more carbon atoms, usually 16 or 18 carbon atoms.
More recently, lipid emulsions for intravenous nutrition which contain triglycerides of medium chain fatty acids (MCTs) have become available. MCTs are triglyceride esters of fatty acids which contain a preponderance of C.sub.8 and C.sub.10 fatty acids (caprylic and capric acid, respectively). Emulsions of this type are disclosed in European Patent Application 0071995 and Eckart et al., "Journal of Parenteral and Enteral Nutrition" v 4(4):360-366, 1980. The above cited European patent application discloses an isotonic emulsion of LCTs and MCTs for parenteral use which contains a fat content of 3 to 30%, an LCT/MCT ratio between 4/1 and 1/4, a physiologically unobjectionable polyhydric alcohol and egg phosphatide as emulsifier.
MCTs are believed to be primarily metabolized in the liver, at least when administered orally, but a substantial proportion of MCTs are metabolized in the peripheral organs such as muscle. Since MCTs are more readily used for caloric energy than LCTs it would be desirable to ensure that exogenously administered MCTs are metabolized by organs having high energy requirements consequent to tissue repair and regeneration. Also, it would be desirable to reduce metabolism of MCTs by healthy organs in order to lessen the release of medium chain fatty acids from the MCTs, thereby sparingly potential medium chain fatty acid toxicity.
Thus a need exists for reducing MCT metabolism in the organs of the body not involved directly in such tissue repair and regeneration.